1. Field of the Invention
The present invention relates to a secure device having a key management function used for content protection and an information processing apparatus. More particularly, the invention relates to a secure device having a key management function used for recording or reproducing digital contents obtained in a digital broadcast or the like and to an information processing apparatus in which the secure device is assembled.
2. Description of the Related Art
Today, digital content sent in a digital broadcast is large-amount data. Consequently, as a recording device for recording digital content, a hard disk (called HDD) or the like is used. However, if digital content is simply stored as it is into an HDD, the digital content can be freely copied and illegally used.
Therefore, in a digital content recording/reproducing apparatus such as a DVD recorder, dedicated hardware (LSI) is undetachably mounted. Obtained digital content is encrypted with a peculiar key recorded in the hardware and, after that, the content is stored in an HDD.
The digital content stored in the HDD is decrypted by the hardware and then reproduced.
With the configuration, even if an HDD storing content is stolen, without the hardware used for the encrypting, the content cannot be reproduced.
In the case of recording/reproducing digital content on an open platform such as a PC, application software for recording or reproducing content is always monitored by an LSI. A protection mechanism is provided which prevents the recording/reproducing process of an illegal application program.
To prevent illegal use of restoring or recovering of an HDD storing content, management information (content information) including a content list and a use situation of the HDD is recorded in the undetachable LSI.
In addition, from the viewpoint of copyright protection and the like, to prevent illegal use and illegal outflow of digital content, various security measures have been proposed (see Japanese Patent Publication Nos. 2003-198527, 2004-129227, 2004-342046, and 2005-85188).
In the conventional techniques, however, encrypting and decrypting of digital content are performed by a single LSI mounted.
Specifically, digital content encrypted by an LSI is associated with the LSI in a one-to-one corresponding manner. Consequently, in the case of performing a digital content reproducing process, a process of moving digital content to a DVD medium or the like, a process of distributing digital content to another information processing apparatus in accordance with the DTCP-IP, and the like, the digital content has to be decrypted by using the same LSI.
Generally, in the case of performing encrypting, decrypting, or the like of content, an LSI can perform a process on only single content, and cannot simultaneously perform a process of reproducing content A in the device and a process of distributing another content B to another device.
Digital content is generally large and, in some cases, it takes long time to perform the process of distributing the digital content. It is inconvenient for the user that the content reproducing process cannot be performed by the same device during the distributing process. That is, an apparatus satisfying a request for simultaneously reproducing and distributing a plurality of pieces of content is in demand.
On the other hand, if the number of pieces of content which can be processed at the same time coincides with the number of LSIs, by mounting a plurality of LSIs, the plurality of pieces of content can be simultaneously processed. For example, by mounting ten LSIs, ten different reproducing, recording, and distributing processes can be simultaneously performed.
However, the location of each piece of content used in the LSIs at present, whether each pieces of the content is being reproduced or distributed, and the like have to be managed. Content information recorded in the LSIs has to be synchronized among the LSIs. The information management and control are very complicated, and increase the cost of the device itself.
As described above, security is assured by prevention of an illegal use of digital content in a manner similar to the conventional techniques and, moreover, it is desired to satisfy the request for simultaneous use of a plurality of pieces of content, prevention of increase in the cost, and prevention of complication of a development process.